My favorite on your list is Roxana--so sweet with Rosalind, but I'm a sucker for alliteration. Fiammetta is also gorgeous. Our name tastes are vastly different for the most part, but some ideas you might like:

I think Serafina would be fabulous with Rosalind! Both romantic, whimsical, pretty, lots of pretty nicknames, and sturdy.

I actually like all the names on your list apart from Fiammetta and Natasha. I find Fiammetta to be quite a lot clunkier than the beautiful Rosalind, though the nn Fia is adorable (if you were to use it - Roo and Fia would be fabulous!). As for Natasha, I'm sorry but it just screams chav to me! Most of the Natasha/Tasha's I know are in their 20's-30's so it feels quite dated to me. Not a fan.